Print certain emails using Postfix, Sieve and Cups - Linux

This is a discussion on Print certain emails using Postfix, Sieve and Cups - Linux ; Good evening at all,
I've got a little problem here and didn't find any answers yet. I've
tried to setup a sieve script which should redirect emails from
particular senders or to particular recipients to an alias called print.
I ...

Print certain emails using Postfix, Sieve and Cups

Good evening at all,

I've got a little problem here and didn't find any answers yet. I've
tried to setup a sieve script which should redirect emails from
particular senders or to particular recipients to an alias called print.
I have set up the alias
print: "|lpr -Plp"

When I send an email from the bash to print everything works fine and
the email is printed. When I send an email from outside the email is
just dropped in the normal mailbox without printing. I changed the
redirect destination in the Sieve script to another email address and it
worked just fine. I don't know what could be wrong here. I also checked
my cups log. There is no attemped by postfix to use lpr.
Anybody an idea???
Thanks for your help